Eliezer S. Yudkowsky wrote:
>JKC has noted that evolution has put a tremendous amount of effort into>detecting and concealing lies, so a perfect truth machine is unlikely.>>I say exactly the opposite: Evolution has put so much effort into lies>that there's probably a module of the brain devoted to lying (anyone>know if someone's looked for it?), and thus it might be very easy to>detect activity with an fMRI. Evolution baffles verbal and kinesic>perceptions, but would have absolutely no reason to defend against>neuroimaging. The inventor might not even need much cognitive science;>a neural net might be very easily trainable to decode "lying" brain activity.

I haven't read the book, though it should arrive today from amazon.com.

With a truth machine, people would want to avoid intellectuals, cynics,
and others who point out how their "sincere" beliefs are inconsistent and
self-serving. After all, if they listened to such critics they might
adopt beliefs which would hurt them socially. "In all likelihood, I'll
only love you this much for a week." I fear people might instead begin
a strong and perhaps bloody supression of critical voices. Sorta like
what happens in war time suppressing those who aren't sure the war is a
good idea, only much more so.